Having trouble finding lenght

Zulgok

Junior Member
Joined
Oct 4, 2015
Messages
53
Hi, I have to find AO2 lenght. What I was given is A1O1=3, AO1=6. Space between two circles could be AO2 middle, but I have nothing to prove it, because I dont know anything about that larger circle, only that its proportional. What is there that I dont notice ? If possible, Id love to receive a direction or hint :p.

D45dA1p.jpg
 
Hi, I have to find AO2 lenght. What I was given is A1O1=3, AO1=6. Space between two circles could be AO2 middle, but I have nothing to prove it, because I dont know anything about that larger circle, only that its proportional. What is there that I dont notice ? If possible, Id love to receive a direction or hint :p.

D45dA1p.jpg
\(\displaystyle \Delta AA_1O_1~\&~\Delta AA_2O_2\) are similar right triangles. Let \(\displaystyle D\) denote the point at which the circles are tangent. Then \(\displaystyle A_1O_1=O_1D~\&~DO_2=O_2A_2\) .
Therefore use proportions.
 
Out of [FONT=MathJax_Math-italic]A[/FONT][FONT=MathJax_Main]1[/FONT][FONT=MathJax_Math-italic]O[/FONT][FONT=MathJax_Main]1[/FONT][FONT=MathJax_Main]=[/FONT][FONT=MathJax_Math-italic]O[/FONT][FONT=MathJax_Main]1[/FONT][FONT=MathJax_Math-italic]D[/FONT][FONT=MathJax_Main] [/FONT][FONT=MathJax_Main]&[/FONT][FONT=MathJax_Main] [/FONT][FONT=MathJax_Math-italic]D[/FONT][FONT=MathJax_Math-italic]O[/FONT][FONT=MathJax_Main]2[/FONT][FONT=MathJax_Main]=[/FONT][FONT=MathJax_Math-italic]O[/FONT][FONT=MathJax_Main]2[/FONT][FONT=MathJax_Math-italic]A[/FONT][FONT=MathJax_Main]2[/FONT]A1O1=O1D & DO2=O2A2 proportion I got that AO2 is 3 times bigger than AO1. So AO2​=18. Is this correct ?
 
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